DESCRIPTION: The failure of most previous studies to find nicotine replacement to be more effective in heavier, more addicted smokers may reflect an inadequate dose of nicotine replacement. Therefore the proposed study is designed to examine the efficacy of a smoking cessation treatment program for heavy smokers which combines high-dose nicotine replacement via a transdermal system with a self-help behavioral intervention. The primary aim of this project is to compare the efficacy of a high-dose pharmacological intervention (transdermal nicotine 42 mg/day) to standard therapy (transdermal nicotine 21 mg/day), both combined with a self- help/minimal intervention (relapse prevention program), in achieving 12- month abstinence in a diverse sample of 400 heavy smokers (>25 cigarettes per day), using a randomized, double-blind, controlled design. The secondary aims of this project are to examine the utility of signal detection methods for improving relapse prediction and treatment subject matching and to examine the temporal relationship of craving and depressed mood with relapse to confirm preliminary findings that change in mood during cessation predicts later relapse in three-month quitters.